Microwave reduction of graphene oxide

The reduction of Graphene Oxide (GO) has become the widely accepted route to obtain graphene like materials for bulk scale production. The commonly used methods of reduction include chemical and thermal routes. But these processes often demand the use of toxic chemicals or exposure to high temperatures for prolonged time that leads to a higher cost of production. In recent years, many non-chemical reduction methods have garnered attention and microwave reduction has emerged as a suitable alternative due to its accelerated and volumetric heating approach. Graphene owing to the presence of π electrons in its structure is a good microwave absorber, but upon oxidation the oxygen functional groups on graphene make it insulating and unresponsive to microwaves. This paper reviews some non-chemical reduction techniques, the mechanism of microwave heating and provides a comprehensive account of microwave reduction of GO organized in two main categories: (i) solid state microwave reduction and (ii) solvent assisted microwave reduction. Additionally, the methods to improve microwave reduction which also covers the concept of hybrid microwave heating are elucidated in detail. We believe that microwave reduction of GO has the potential for mass scale production of graphene-based materials.